Sharif Digital Repository

The paper presents further experiments with an extended version of a comprehensive model for assessment of energy technologies and research and development (R&D) planning to evaluate the impact of innovation programs on development of Iranian electricity-supply system. This analytical instrument is a model of energy R&D resource allocation with an explicit perspective of developing countries which has been linked to a bottom-up energy-systems model. Three emerging electricity generation technologies of solar PV, wind turbine and gas fuel cell are considered in the model and the impact of innovation programs on cost-reducing innovation for them is examined. The main results provided by the... 

The effect of substitutional Li doping into NiOx hole transporting layer (HTL) for use in inverted perovskite solar cells was systematically studied. Li doped NiOx thin films with preferential crystal growth along the (111) plane were deposited using a simple solution-based process. Mott-Schottky analysis showed that hole carrier concentration (NA) is doubled by Li doping. Utilizing 4 % Li in NiOx improved the power conversion efficiency (PCE) of solar devices from 9.0 % to 12.6 %. Photoluminescence quenching investigations demonstrate better hole capturing properties of Li:NiOx compared to that of NiOx, leading to higher current densities by Li doping. The electrical conductivity of NiOx is... 

N-annulated perylene based materials show outstanding and tunable optical and physical properties, making them suitable to be charge transport materials for optoelectronic applications. However, this type of materials has so far not been well studied in solar cells. Here, we develop a new hole transport material (HTM), namely S5, based on perylene building block terms, for organic-inorganic hybrid perovskite solar cells (PSCs). We have systematically studied the influences of the film thickness of S5 on their photovoltaic performance, and a low concentration of S5 with a thinner HTM film is favorable for obtaining higher solar cell efficiency. S5 shows excellent energy alignment with... 

This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency... 

One of the efficient solar energy harvesting technics is the parabolic trough concentrated solar power plant. However, if the concentrated solar power plant were not equipped with a storage system, the power plant capacity factor would be deficient. Latent thermal energy storage system using phase change material (PCM) is a high energy density storage system to provide durable energy with a constant temperature. In this study, first, a dynamic analysis is performed implementing TRNSYS software on the parabolic trough concentrated solar power plant located in Shiraz, Iran. Consequently, this system is assisted by the latent thermal energy storage system to improve its performance and capacity... 

Photovoltaic energy is one of the clean and efficient energies which has been developing quickly in the last years. As the penetration of solar plants is increasing in the electricity network, new problems have arisen in network operation. This paper models a high penetration factor of solar energy in the electricity network and investigates the impact of solar energy growth on both the generation schedule of different power plants and in the natural gas transmission network. Fuel management of gas power plants is modeled through simulation of the natural gas transmission network. To this end, an increase in the penetration of solar energy in the electricity network inevitably leads to a... 

Global warming escalation has extended average temperature of earth beyond its safe limit. To avert this environmental-threat, solar energy has acquired substantial attention of remarkable researchers in this century. To effectively utilize solar energy by transforming into thermal and electrical energy, the involvement of nanofluids having intensified thermal, optical and magnetic properties, has become very popular. The foremost objective of this article is to provide a comprehensive review on the applications of nanofluids in solar energy systems like solar collectors, photovoltaic cells, solar stills, and thermal energy storage, which are thoroughly discussed in this paper. The effect of... 

One of the primary factors affecting the amount of worldwide energy consumption and greenhouse gas emissions is cooking. Solar cooking is an appropriate solution because it is both inexpensive and expandable. To illustrate modern advancements and the current status of solar cooking technology, this paper presents a review of recent experimental and analytical socioeconomic studies on solar cookers. The experimental studies have been divided into three categories based on different solar cooker structures: (i) box types, (ii) concentrating types, and (iii) panel types. Next, different designs are investigated according to their direct or indirect heat transfer modes and optional equipment for... 

In this work, the combination of H2O2 and an active visible-light-driven photocatalyst (Ag-S/PEG/TiO2) was utilized under natural solar radiation for the degradation of 2-nitrophenol (2-NP), and interaction effects between the photocatalyst and hydrogen peroxide were analyzed. For this purpose, experiments were designed using the response surface methodology based on the central composite design. The resulting data was utilized to obtain a model for the prediction of response (the degradation efficiency) as a function of two independent factors (H2O2 concentration and the photocatalyst loading). The statistical analysis indicated that optimum values of each of the two independent factors... 

Solar updraft tower (SUT) is a simple power plant in which ventilation of heated air inside a channel drives a turbine. This system is recognised as suitable for areas with abundant solar radiation. As a result, there is no extensive research on the performance of SUTs under mild solar radiation. Studies show that strong ambient crosswinds can affect the performance of a SUT. In this paper, the efficiency of SUTs in areas which benefit from strong winds, despite low solar radiation, is investigated through numerical modelling. Comparison is made between the efficiency of a commercial-scale SUT in Manzanares (Spain) with intensive solar radiation, and one of the same size potentially located... 

Although morphological disorder of nanotube structure is further down than the nanoparticular electrode, its density of traps are the hindering effects in the charge transport. In this study, crack-free TiO2 nanotube membranes, which obtained through a re-anodizing process, are fixed on transparent fluorine–tin-oxide glass by applying a few drops of Titanium Isopropoxide without needing the TiO2 powder paste. Front-side illuminated dye sensitized solar cells fabricated by undoped, N-doped and blue TiO2 nanotube membranes are investigated. The electrical characteristics of TiO2 nanotube based dye sensitized solar cells are followed by theoretical analysis using simple one-diode model.... 

Isolated microgrids depend mainly on diesel generation and have polluting transportation. This is being addressed by the introduction of renewable energy resources and electric vehicles (EVs). Hence, this paper presents a novel long-term planning model for the introduction of EVs in isolated microgrids. This work studies the replacement of internal combustion vehicles with electric ones by analyzing their respective investment, maintenance and operation costs. Various case studies are discussed, considering different EV and solar photovoltaic (PV) penetration levels, and varying prices of diesel in the planning horizon. Results demonstrate that investing in EVs could significantly reduce net... 

This paper addresses a low complexity and high efficient cooling system applicable on photovoltaic (PV) system leading to enhance electrical efficiency and provide preheated water. The developed system consists of a photovoltaic panel, a cooling water system establishing a uniform surface temperature, and a solar water heater. According to the proposed system characteristics, the setup is constructed based on a single mono-crystalline solar panel to absorb more solar radiation intensity and generate more electrical energy per area in compare to a poly-crystalline panel. The preheated water produced by absorbed heat from the photovoltaic is conducted to a solar water heater to satisfy... 

Extraction of thermal heat from a salinity-gradient solar pond (SGSP) as a way of accumulating solar energy, stockpiling and taking merit of it for medium and low temperature demands is presented as an interesting topic in recent decades. This reliable supply of heat can be used for low-temperature refrigeration systems to yield cooling load for residential applications. For this purpose, theoretical investigation of ejector refrigeration cycle (ERC) driven by a SGSP is carried out to produce cooling output. Also, thermoelectric generator (TEG) is used as a potential device replacing condenser of the ERC for the sake of bolstering performance of the fundamental system by producing power,... 

Solar pond is a type of solar collector that stores solar energy in the form of heat. The solar pond can be used as a low-temperature heat source for electricity generation. In this paper, to find the most suitable power cycle for power generation from the solar pond, the performance of the Organic Rankine Cycle (ORC), Trilateral Flash Cycle (TFC) and their modified forms with an open feed liquid heater and an internal heat exchanger for different working fluids was investigated. Water was considered as the heat transfer fluid which transfers the stored heat from the solar pond to the working fluid of the cycle. The results indicate that in all cases, the energy and exergy efficiency of the... 

Wettability is one of the most important factors which significantly influences solar still efficiency. Moreover, it determines the condensation mode, i.e., filmwise or dropwise condensation. In the present study, materials with different wettability were applied as the condensing surface to evaluate the effect of wettability on the distillate production of a single slope solar still. To compare the effects of dropwise and filmwise condensation on the condensate yield, the wettability of the condensing surface was changed by applying a nano-silicon solution according to a dip coating technique. All the experiments were conducted at three surface inclination angles. The results revealed that... 

Recently, graphitic carbon nitride (g-C3N4) has attracted great interest for photo(electro)chemical applications such as sensing, solar energy exploitation, photocatalysis, and hydrogen generation. This paper presents the potential application and benefits of g-C3N4 nanolayers as a green and highly efficient electrode modifier for the detection of trace lead ions in drinking water and urban dust samples. Carbon nitride nanosheets with a thickness of ∼6 A° and lateral of 100–150 nm were prepared through high-temperature polymerization of melamine followed by sonication-assisted liquid exfoliation. A glassy carbon electrode (GCE) was modified by a thin layer of g-C3N4 through drop casting and... 

Stand-alone hybrid power systems are an alternative to main electricity grids, where the grid extension is costly or the trifling local consumption would not justify its expansion. However, lack of consistency and uniformity in renewable energy sources, and the restrictions of energy storage systems make system sizing a challenging task. Optimum size of a stand-alone system depends on several factors including energy demand function. In this paper, different types of demand functions are addressed for optimising a solar-hydrogen supply system. Different parameters are defined to investigate the impact of household population on the power generation cost, and also to determine the optimum... 

In this research, a confined aquifer with low groundwater flow was considered to meet the cooling and heating requirements of residential complexes. The complexes were located in the cities of Ahvaz, Ardabil, Bandar Abbas, Esfahan, Kerman, Rasht, Tehran, and Zahedan. The complex in Ardabil mostly required heating, the ones in Ahvaz and Bandar Abbas mostly required cooling, and the complexes in other cities required both heating and cooling. Four different alternatives of Aquifer Thermal Energy Storage (ATES) were analyzed in this study. These alternatives consisted of using ATES: 1) alone for cooling, 2) coupled with a conventional refrigeration system or a chiller for cooling, 3) by... 

In this research, a confined aquifer with low groundwater flow was considered to meet the cooling and heating requirements of residential complexes. The complexes were located in the cities of Ahvaz, Ardabil, Bandar Abbas, Esfahan, Kerman, Rasht, Tehran, and Zahedan. The complex in Ardabil mostly required heating, the ones in Ahvaz and Bandar Abbas mostly required cooling, and the complexes in other cities required both heating and cooling. Four different alternatives of Aquifer Thermal Energy Storage (ATES) were analyzed in this study. These alternatives consisted of using ATES: 1) alone for cooling, 2) coupled with a conventional refrigeration system or a chiller for cooling, 3) by...